Avro C++
AvroTraits.hh
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18 
19 #ifndef avro_AvroTraits_hh__
20 #define avro_AvroTraits_hh__
21 
22 #include "Config.hh"
23 #include "Types.hh"
24 #include <cstdint>
25 #include <type_traits>
26 
31 namespace avro {
32 
37 template<typename T>
38 struct is_serializable : public std::false_type {};
39 
40 template<typename T>
41 struct is_promotable : public std::false_type {};
42 
43 template<typename T>
44 struct type_to_avro {
45  static const Type type = AVRO_NUM_TYPES;
46 };
47 
55 template<class T>
56 struct is_defined {
57 
58  typedef char yes[1];
59 
60  typedef char no[2];
61 
62  template<class U>
63  static yes &test(char (*)[sizeof(U)]) { throw 0; }
64 
65  template<class U>
66  static no &test(...) { throw 0; }
67 
68  static const bool value = sizeof(test<T>(0)) == sizeof(yes);
69 };
70 
77 template<class T>
79 
80  typedef char yes[1];
81 
82  typedef char no[2];
83 
84  template<class U>
85  static yes &test(char (*)[sizeof(U)]) { throw 0; }
86 
87  template<class U>
88  static no &test(...) { throw 0; }
89 
90  static const bool value = sizeof(test<T>(0)) == sizeof(no);
91 };
92 
93 #define DEFINE_PRIMITIVE(CTYPE, AVROTYPE) \
94  template<> \
95  struct is_serializable<CTYPE> : public std::true_type {}; \
96  \
97  template<> \
98  struct type_to_avro<CTYPE> { \
99  static const Type type = AVROTYPE; \
100  };
101 
102 #define DEFINE_PROMOTABLE_PRIMITIVE(CTYPE, AVROTYPE) \
103  template<> \
104  struct is_promotable<CTYPE> : public std::true_type {}; \
105  \
106  DEFINE_PRIMITIVE(CTYPE, AVROTYPE)
107 
108 DEFINE_PROMOTABLE_PRIMITIVE(int32_t, AVRO_INT)
109 DEFINE_PROMOTABLE_PRIMITIVE(int64_t, AVRO_LONG)
110 DEFINE_PROMOTABLE_PRIMITIVE(float, AVRO_FLOAT)
111 DEFINE_PRIMITIVE(double, AVRO_DOUBLE)
112 DEFINE_PRIMITIVE(bool, AVRO_BOOL)
113 DEFINE_PRIMITIVE(Null, AVRO_NULL)
114 DEFINE_PRIMITIVE(std::string, AVRO_STRING)
115 DEFINE_PRIMITIVE(std::vector<uint8_t>, AVRO_BYTES)
116 
117 } // namespace avro
118 
119 #endif
avro::AVRO_NULL
@ AVRO_NULL
Definition: Types.hh:40
avro::type_to_avro
Definition: AvroTraits.hh:44
avro::AVRO_LONG
@ AVRO_LONG
Definition: Types.hh:36
avro::is_serializable
Define an is_serializable trait for types we can serialize natively.
Definition: AvroTraits.hh:38
avro::is_defined
Check if a T is a complete type i.e.
Definition: AvroTraits.hh:56
avro::AVRO_FLOAT
@ AVRO_FLOAT
Definition: Types.hh:37
avro::AVRO_BOOL
@ AVRO_BOOL
Definition: Types.hh:39
avro::AVRO_STRING
@ AVRO_STRING
Definition: Types.hh:33
avro::AVRO_NUM_TYPES
@ AVRO_NUM_TYPES
Definition: Types.hh:49
avro::AVRO_BYTES
@ AVRO_BYTES
Definition: Types.hh:34
avro::is_not_defined
Similar to is_defined, but used to check if T is not defined.
Definition: AvroTraits.hh:78
avro::is_promotable
Definition: AvroTraits.hh:41
avro::AVRO_INT
@ AVRO_INT
Definition: Types.hh:35
avro
A bunch of templates and specializations for encoding and decoding specific types.
Definition: AvroParse.hh:30
avro::AVRO_DOUBLE
@ AVRO_DOUBLE
Definition: Types.hh:38
avro::Null
define a type to represent Avro Null in template functions
Definition: Types.hh:101
avro::Type
Type
The "type" for the schema.
Definition: Types.hh:31